One example of a machine for processing workpieces is the TruPunch® 5000 punching machine offered by Trumpf Werkzeugmaschinen GmbH+Co. KG. The TruPunch® 5000 punching machine has mono-tool holders, i.e., tool holders to which a single tool, including a tool punch and a tool die, is secured. Further tools are situated in a tool magazine and can be inserted as alternative tools into the mono-tool holders for workpiece processing when required.
The mono-tool holders have a tool punch holder that can be raised and lowered by a hydraulic stroke drive, and a stationary tool die holder. A workpiece table serves to support a metal sheet that is to be processed.
Workpiece processing is effected by lowering the tool punch holder together with a tool punch secured thereto onto the metal sheet supported on the workpiece table. As a result, the tool punch presses on one side of the metal sheet and the tool die presses on the other side of the metal sheet.
The tool punches and the tool dies of the TruPunch® 5000 punching machine have a mushroom-shaped configuration. The tool punches and the tool dies each have a tool shank that is used to secure the tool punches and tool dies to their respective tool holders. The processing devices of the tools in the form of cutting edges or forming bars are provided on tool heads which are radially enlarged relative to the tool shanks.
In designing tools for machines of the type described above, considerable restrictions have to be taken into consideration due to the spatial conditions at the tool holders.
EP 0 417 836 B1 discloses a punching machine in which both a punch holder and a die holder are positionable relative to a workpiece table along a stroke axis in order to compensate for changes in the overall tool heights along the stroke axis due to re-grinding of the punching tools which may be necessary from time to time. Despite those positioning movements for compensating for the slight reduction in the tool heights due to wear, the punching tools for the punching machine known from EP 0 417 836 B1—just as in the case of the TruPunch® 5000 punching machine—are subject to considerable restrictions due to the spatial conditions at the tool holders.